Getting internal clocks to run on NRF54l15

RE: Getting internal clocks to run on NRF54l15

jgarv743 — Thu, 22 Jan 2026 21:57:07 GMT

It is working! There actually appear to be two issues which is what was slowing me down so much. The initial set up of the clocks was a problem, But also logging before something was ready was causing it to hang. This thread can be closed

RE: Getting internal clocks to run on NRF54l15

jgarv743 — Thu, 22 Jan 2026 18:37:00 GMT

Oh shoot my bad! Didnt realize the NRF# wasnt the full info. I am using

https://www.digikey.com/en/products/detail/u-blox/NORA-B206-00B/26163316?gclsrc=aw.ds&gad_source=1&gad_campaignid=120565755&gclid=CjwKCAiAssfLBhBDEiwAcLpwfqWPn3x-8agXqVeLRB9OhYzMLBUKvMwrghcGcHqGrwjzeeiikK6CWxoCMBgQAvD_BwE

which is the Ublox, i will check their docs!

RE: Getting internal clocks to run on NRF54l15

Turbo J — Thu, 22 Jan 2026 18:32:55 GMT

This is the first time you mentioned using an Ublox NORA-B2 module. We cannot read your mind.

And yes, these modules should have the HFXO crystal included. Might want to check ublox documentation how to to configure the NCS SDK.

RE: Getting internal clocks to run on NRF54l15

jgarv743 — Thu, 22 Jan 2026 18:27:50 GMT

sorry if im totally missing something here, doesnt this suggest that the internal xtal can be used for the hfxo? or can it not calibrate off that

RE: Getting internal clocks to run on NRF54l15

jgarv743 — Thu, 22 Jan 2026 18:24:22 GMT

I have added to the dts

&hfxo {

load-capacitors = "internal";

load-capacitance-femtofarad = <15000>;

};

which should set up the internal 32M as i understand it

prj.conf now matches the post i linked as well.

### Clock ###

CONFIG_CLOCK_CONTROL=y

CONFIG_CLOCK_CONTROL_NRF=y

CONFIG_NRFX_CLOCK=y

CONFIG_NRF_GRTC_TIMER=y

CONFIG_NRF_GRTC_START_SYSCOUNTER=y

CONFIG_NRFX_GRTC=y

CONFIG_NRFX_CLOCK_LF_SRC_RC=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_SYNTH=n

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION=y

CONFIG_CLOCK_CONTROL_NRF_CALIBRATION_LF_ALWAYS_ON=y

doing this my error has changed to
nrf/drivers/mpsl/clock_control/nrfx_power_clock.h:11:2: error: #error "Expected disabled nrfx_clock."
if i disable the config nrfx clock though i end up right back where i was

RE: Getting internal clocks to run on NRF54l15

Turbo J — Thu, 22 Jan 2026 18:08:05 GMT

You need a physical crystal to be present. Otherwise you can't calibrate the LFRC as there is nothing to calibrate against. LFRC calibration requires HFXO.

RE: Getting internal clocks to run on NRF54l15

jgarv743 — Thu, 22 Jan 2026 15:56:30 GMT

1. The logs dont output, they did before this clock issue, but something here is spinning before that gets initialized. Our good friend claude (ai) was telling me that the logging was coming up after the clock stuff so those calls might be sticking.

2. Are you saying i need a physical crystal? or just that hfxo needs to be enabled.

As for submodules i do have a bootloader folder that has mcuboot that came from either zephyr or west or the nrf download. I dont believe im using it (following the cli example which could be using it) so all my config stuff is in the main prj.conf, the zephyr.dts file looks like the clocks are all being set as expected

RE: Getting internal clocks to run on NRF54l15

Håkon Alseth — Thu, 22 Jan 2026 11:28:44 GMT

Hi,

Based on frames 3-7, it looks like the firmware is trying to log.

Q1: Is there any log output over uart that you can share?

Q2: Do you have any sub-images, like mcuboot, enabled? If yes, you need to add 32k RC oscillator configuration to the configuration there as well.

[quote user=""]

in my dts i have:

&hfxo {

status = "disabled";

};

[/quote]

For any application that uses the radio (and some other functions, like RC osc calibration), you will need to use HFXO.

Kind regards,

Håkon